mysterious air in y plan

[Viper Gas]

Hello All,

I have an interesting question to ask regarding mysterious air entering into a
Y plan system
gravity fed with f&e tank and a cwsc
Ideal floor standing heat only boiler over 20 years old
Honeywell mid position valve
Hot water cylinder.

Air is entering into the system so much so every day the rads need to be substantially bled. There is no evidence of water leaks or damp patches so I'm thinking that the old cast iron boiler maybe compromised. Ie the boiler is perforated/cracked and therefore allowing water to evaporate into the air under the heat of the boiler. I hope that makes sense?
Has anyone had the same kind of issue?

Any valid responses will be greatly appreciated.
Dd368

 

[kay-jay]

Not air. It will be hydrogen which is created as a by product of corrosion.
Open bleed valve slightly and light it with a lighter. If it ignites its hydrogen and you will need a power flush and chemical treatment.

 

[jam1979]

Some times you can smell it when you bleed the rads it smells a bit like gas

 

[brum]

well guys learnt something tonight cheers...brum

 

[turnpin]

Not air. It will be hydrogen which is created as a by product of corrosion.
Open bleed valve slightly and light it with a lighter. If it ignites its hydrogen and you will need a power flush and chemical treatment.

Plus a new set of eyebrows and a new fringe...lol regards Turnpin:66:

 

[Viper Gas]

Hydrogen? Can that really account for bleeding everyday?

 

[Viper Gas]

Also you mentioned powerflush and chemical treatment. Which chemicals would you recommend?

 

[kay-jay]

Also you mentioned powerflush and chemical treatment. Which chemicals would you recommend?

A good cleaner sentinel x300 or fernox f3 and some good inhibitor x100/f1.

Yes if you have advenced corrosion hydrogen builds up quickly.

Also if there is a lot of sludge/magnetite from corrosion it can cause circulation problems and cause pumping over into the feed and expansion tank which ensures re-oxygenated water keeps entering the system which speeds up corrosion.... vicious cycle

 

[newcastle phill]

My old system had that.

PING - and loads of muck all over kitchen floor. Boiler dead

 

[Viper Gas]

Thank you. I will do the lighter test.

 

[Leo21]

Look at the cold fill and vent arrangement, also could be sucking down the expansion due to sludged up system.

 

[townfanjon]

I would use my nose before a lighter, far to risky LOL

 

[AWheating]

run a magnet on the pipework around the feed and vent connections etc......

whats the system water condition like? check out the water in the header tank.

 

[happyflyer]

I would use my nose before a lighter, far to risky LOL

The vent key gets that hot you can't touch it, then black water on the carpet, been there, wrote the book, you cant see the flame, A&E, use your nose like the man says, bad eggs smell.

 

[Viper Gas]

The vent key gets that hot you can't touch it, then black water on the carpet, been there, wrote the book, you cant see the flame, A&E, use your nose like the man says, bad eggs smell.

I have to say lads that the system is displaying other symptoms.
1. There is a manual air vent about 20 cm away from the mid pos valve which gets full of air in minutes and I think is causing the valve to not function correctly. IE rads get hot when there is only demand for hot water . This could be due to build up of sludge not allowing the gates to close fully.
2. I manually overfilled the f and e tank and allowed it to drain down to the over flow pipe. I came back 40 min later and I found the water level had dropped a further inch. Where did the water go?
Thank you for your time.

 

[solutions]

2. I manually overfilled the f and e tank and allowed it to drain down to the over flow pipe. I came back 40 min later and I found the water level had dropped a further inch. Where did the water go?
Thank you for your time.

In to the system as air was pushed out. As is intended.
Sounds like your 3 port may be goosed probably because it appears you have a very dirty system. you may also have pumping over in to the f and e if their are blockages around the 3 port pump or in the feed pipe. Pumping over can cause excessive corosion and nitrogen build up with the constant oxygenation of the system water its a vicious cycle. Use the magnet test on the pipework as suggested allready to see if there are any clearly magnetic spots on the copper pipework.

 

[dmheat]

Cold feed is a neutral point, it should be positioned between the open vent and pump, if it's blocked or partially blocked the pump will draw air in via the open vent pipe, as it'll be "neutralising" naff all if it's restricted. This will happen as soon as the pump turns on, corrosion/oxygenated water is a valid point, but purely corrosion won't give you that much hydrogen in 20minutes.

Previous posters are surely correct, get that system cleaned, AND in my personal opinion, reconfig the ov and cf arrangement.

3 port will pass on a dirty system, paddle/ball not able to seal off ports as there is **** on the valve seat

 

[Viper Gas]

Thanks to all posters it's been educational.

 

[happyflyer]

DD,

It might be educational but is it sorted???